OVERVIEW

The SM5849AF is a digital audio signal, asynchronous sample rate converter LSI. It supports 16/20/24-bit word length input data, 16/20/24-bit word length output data, 2kHz to 100kHz input sample rate range, and 4kHz to 200kHz output sample rate range. It also features a built-in digital deemphasis filter and digital attenuator.

FEATURES

Functions

■ Left/right-channel processing (stereo)

■ 2 to 100kHz input sample rate range (fsi)

■ 4 to 200kHz output sample rate range (fso)

■ 0.45 to 2.2-times variable sample rate conversion ratio (fso/fsi)

■ Asynchronous input and output timing (clock inputs)

■ System clock inputs (input and output clocks inde pendent)

? 256fsi or 384fsi input system clock select

? 256fso or 384fso output system clock select

■ Deemphasis filter

? IIR-type filter

? 44.1, 48 or 32kHz

■ Digital attenuator

? 11-bit data, 1025 levels

? Smooth attenuation change

? +12dB gain shift function

■ Direct mute function

■ Through mode operation

? Direct connection from input to output

■ Output data clocks (LRCO, BCKO)

? Slave mode: external input

? Master mode: output system clock generated internally

■ Dither round-off processing

? Dither round-off ON/OFF selectable

■ 3.3V single supply

■ 80-pin QFP

■ Silicon-gate CMOS process

Filter Characteristics and Converter Efficiency

■ 24-bit internal data word length

■ Deemphasis filter characteristics (IIR filter)

? ±0.03dB gain deviation from ideal filter charac teristics

■ Anti-aliasing LPF characteristics

? Output/input sample rate conversion ratio automatic filter select (6 FIR filters)

- Up converter LPF

1.0 to 2.2 times

- Down converter LPF I

0.92 times: 48.0 to 44.1kHz

- Down converter LPF II

0.73 times: 44.1 to 32.0kHz

- Down converter LPF III

0.67 times: 48.0 to 32.0kHz

- Down converter LPF IV

0.5 times: 48.0 to 24.0kHz

- Down converter LPF V

0.45 times: 48.0 to 22.1kHz

? ±0.00005dB passband ripple

? > 110dB stopband attenuation

■ Converter noise levels

? ≤ ?110dB internal calculation (quantization) noise

? ?98dB (16-bit output), ?122dB (20-bit output), and ?146dB (24-bit output) word rounding noise

■ Output S/N ratio (theoretical values)

Interfaces

■ Input data format

? 2s-complement, L/R alternating, serial

? IIS/non-IIS format

■ Output data format

? 2s-complement, MSB first, L/R alternating, serial

? Continuous bit clock

APPLICATIONS

■ Digital audio equipment-interface sample rate conversion (AV amplifiers, CD-R, DAT, MD and 8mm VTRs)

■ Commercial recording/editing equipment sample rate conversion